Experiment on no-flow and flow CO2-water–rock interaction: A kinetics calculation method for rock pore evolution

Abstract

Carbon capture and storage (CCS) technology is an important measure to reduce carbon emissions, and the safety of CCS projects largely depends on the physical and chemical processes of CO2-water–rock interactions in reservoirs. As the important petrophysical parameters of reservoir rocks, the change trends of pore structure parameters are usually ignored and thus difficult to quantitatively master. In this study, non-flow and flow interaction tests were performed under the premise of considering the flow effect of liquid environment. Based on chemical kinetics method, the reaction kinetics equation was first established, and the different reaction mechanisms of soluble and insoluble minerals were clarified. In flow interactions, the dissolution of soluble minerals is weakened and the precipitation of insoluble minerals is enhanced. The evolution trends of pore structure parameters were further analysed to find the inhibited pore evolution process by flow effect. A kinetics method was proposed to calculate the pore evolution process. The dominantly controlling effect of soluble minerals on the pore evolution process was illustrated by correlation analysis, and a prediction method for porosity increment was proposed based on the reaction extent of soluble minerals. Eventually, the CO2-water–rock interaction mechanism was clarified from the mineral level.